The present invention relates to a laser sighting device for projecting a laser beam in a horizontal or in a vertical direction and forming a laser irradiation reference plane or for projecting a light beam to form a reference point.
As a conventional type laser sighting device, a device is known, which irradiates a laser beam compensated for vertical irradiation via a rotating pentagonal prism and forms a horizontal laser irradiation reference plane. Also, a device is known, which is tilted at an angle of 90 degree. and irradiates a laser beam similarly via a rotating pentagonal prism and forms a vertical laser irradiation reference plane.
Also, a laser sighting device is known, which irradiates a laser beam in one direction or in a plurality of directions and forms one reference point or a plurality of reference points.
The laser sighting device for forming the laser irradiation reference plane or the laser sighting device for forming the reference point as described above may be designed as an independent laser sighting device respectively, while these may be integrated together from economical reason. That is, a part of the optical system is designed as replaceable or the entire optical system may be designed as replaceable as a unit so that the optical systems can be used respectively depending on each purpose of use, and formation of the laser irradiation reference plane and formation of the reference point can be achieved by the use of a single laser sighting device.
In the laser sighting device, for the purpose of forming a reference plane or a reference point accurately, the irradiating direction of the laser beam must be accurately compensated in a vertical or horizontal direction.
In the laser sighting device, which can form the laser irradiation reference plane and the reference point, a tilt sensor comprising a bubble tube is provided to perform leveling operation of the laser sighting device itself so that the laser beam can be irradiated in the vertical or horizontal direction.
However, in the conventional type laser sighting device, in which the optical system can be replaced, the rotary prism can be removed or inserted, or the entire optical system can be replaced depending on the intended purpose. However, there has been provided no means for performing positioning of the optical system and laser sighting device main unit, i.e., there has been provided no means for detecting the relationship between an optical axis of the optical system and the reference angle of the tilt sensor. For this reason, the optical axis of the optical system is deviated with respect to the reference angle of the tilt sensor and the laser irradiation plane or the laser irradiation line is often extremely deviated from the vertical direction or the horizontal direction.